He was born on the Lower East Side of Manhattan on the 20th of October, 1958. His father, Viggo Sr, was Danish, while his mother was American. The couple had met in Norway and married in Holland, in a Lutheran ceremony. Though he came from farming stock in Denmark, Viggo Sr was set on becoming a businessman and, hoping to make his fortune, in 1960 moved his family (Viggo has two younger brothers) to South America. Here they would shift between Buenos Aires in Argentina and Venezuela, often spending holidays back in Denmark, on the Mortensen family farm.

Viggo Mortensen has always been involved in the arts. Although Viggo only began studying acting in his early twenties, Mortensen was already an accomplished photographer and an up-and-coming poet and painter. After travelling to, and living in, places like Venezelua and Denmark, Viggo Mortensen decided to go back to his hometown of New York City and take acting lessons. Viggo Mortensen landed the role of an Amish farmer in the oscar-winning flick Witness in 1985, but did not snag any other mainstream movie roles for almost a decade. Finally, in the 1990s, Viggo Mortensen began to score some major roles in movies like Carlito's Way, G.I. Jane and A Perfect Murder with Gwyneth Paltrow.

Viggo Mortensen's biggest role is playing Aragorn, Future King of Gondor, in The Lord of the Rings trilogy. Viggo Mortensen almost didn't take the role because it meant he would be away from his son for over a year (while filming in New Zealand.) Also, the role of Aragorn Courtesy of New Line had already started filming with another actor, Stuart Townsend, and Viggo Mortensen did not like the idea of taking over the role from someone else. Luckily, his son told him he had to take it and Viggo Mortensen listened. The title of the third installment of the Lord of the Rings trilogy, Return of the King, refers to Aragorn's return to Gondor.

He is also an accomplished poet, photographer and painter, and is currently working on his fourth book of poetry. Gallery showings of his photography and paintings have been featured in New York, Los Angeles, Cuba, Denmark, and New Zealand. He has released three Jazz CDs and several books of poetry including, Ten Last Night and Recent Forgeries.